Hello, Philippe, I've attached a picture of the roll scanner that a
friend and I made a couple years ago.  There is also a scan of a tune
from a recently acquired organ, just to show what the resulting scans
are like.  Mostly, I've use it to investigate the tuning of the
associated organs or to identify tunes.

I've only done a few and I can tell you that it is a _very_ difficult
problem.  Even if you have the actual organ so you can tell the general
arrangement of the pipes etc., it is not easy.  It is _much_ easier if
you can recognize at least one tune on the barrel.  I spent 6 hours on
the first one, a 26-key Poirot organ whose pipes were mostly missing.
The only clue was the approximate order of the notes and one tune.
I also spent several hours trying to decode a barrel from an 11 key
serinette.  I think I was having a brain cramp -- I knew the order of
the notes but could not figure out the non-chromatic spacing.

The reader scans the individual notes into MIDI through an Octet
converter into my computer.  I then use Cakewalk to re-arrange the
notes into proposed tunings until I hit on the correct arrangement of
keys.  Then I use a CAL program (kindly supplied by a friend from the
Rollscanners group) to automatically convert the rest of the tunes on
the barrel.  It ain't easy but it's a lot less work and damage than
trying to do it on the real organ (if you have it).

Regards,
Craig Smith
near Rochester, New York USA